Advertisements
Advertisements
Question
The density of iron crystal is 8.54-gram cm–3. If the edge length of the unit cell is 2.8 A° and atomic mass is 56 gram mol–1, find the number of atoms in the unit cell. (Given: Avogadro's number = 6.022x1023,1A° = 1x10-8 cm)
Advertisements
Solution
Given a = 2.8Å = `2.8 xx 10^(-8)` cm
Molar Mass = 56 gm
Density = 8.54 g cm-3
Volume = (a)3
`= (2.8 xx 10^(-8))^3`
`= 21.95 xx 10^(-24) cm^3`
Density of unit cell = `"Mass of unit cell"/"Volume of unit cell"`
∴ Mass of unit cell = density x volume
`= 21.95 xx 10^(-24) xx 8.54`
`= 187.47 xx 10^(-24)`
56 gm of Fe contains 6.022 x 1023 atoms
`187.47 xx 10^(-24)` gm Fe contain = `(6.022xx10^23 xx 187.47xx10^(-24))/56`
= `20.15xx 10^(-1)`
= 2.01
= 2
Number of atoms in unit cell is 2.
APPEARS IN
RELATED QUESTIONS
Choose the most correct answer.
In crystal lattice formed by bcc unit cell, the void volume is _______.
Choose the most correct answer.
A compound forms hcp structure. Number of octahedral and tetrahedral voids in 0.5 mole of substance is respectively _______.
The coordination number of spheres in the hcp lattice in three dimension is ______.
The number of tetrahedral voids are formed if the number of atoms in a crystal is N/2.
The number of octahedral voids formed in 0.5 mol of a compound forming hcp structure?
A metal crystallizes in bcc lattice with edge length 4.48 Å. The radius of the metal atom is ___________ Å.
The ratio of close-packed atoms to tetrahedral holes in cubic close packing is ____________.
Xenon crystallises in fcc lattice and the edge length of unit cell is 620 pm. What is the radius of Xe atom?
The coordination number of each sphere in bcc lattice is ____________.
In two dimensional AAAA type packing, the coordination number of each sphere is ____________.
The coordination number of Rh in the complex [Rh(NH3)3(SCN)3] is ____________.
In ABCABC type arrangement of spheres, the coordination number of any sphere is __________.
Zinc forms hcp structure. What is the number of octahedral voids formed in 0.2 mol of it?
What is the coordination number of cation in ionic compound if the type of hole occupied by cation is cubic?
What is the coordination number of cation in ionic compound if the type of hole occupied by cation is octahedral?
Which among the following metals crystallise as a simple cube?
What is the coordination number of atoms in bcc crystal lattice?
The coordination number of cobalt in the complex [Co(en)2Br2]Cl2 is ______.
Predict the type of cubic lattice of a solid element having edge length of 400 pm and density is 6.25 g/ml.
(Atomic mass of element = 60)
Calculate the total number of tetrahedral and octahedral voids formed in 0.6 mol of a compound if it forms hcp structure.
Find the total number of tetrahedral and octahedral voids formed in 1 mole of a compound forming hcp structure.
The number of nearest neighbours in a bcc unit cell is ______.
A metallic crystal crystallizes into a lattice containing a sequence of layers AB AB AB......Any packing of spheres leaves out voids in the lattice. What percentage of volume of this lattice is empty space?
Calculate the volume occupied by a particle in a simple cubic unit cell if the volume of the unit cell is 5.5 × 10−22 cm3.
What is the minimum number of spheres required to develop an octahedral void?
